Thread: High idle, decel issues?

I'm having issues where my car idles a little high, and when I'm driving and let off, the ecu doesn't see close throttle and shut off the injectors like it should. When I let off and coast it keeps feeding fuel and causes the car to buck and shake, instead of coast. When I check the signals, the tps shows .52 at idle, so it should see closed. Anybody know what could cause this?

I know on my car even if I let off the gas and put it in nuetral it will still Idle at about 1200 until I come to a complete stop and then itll drop down to about 800. But yeah your Inj should be cutting off when your in gear decelerating. Ill check my readings on my SAFC for the TPS when I let off next time im in the car and let you know where theyre at.

No mine is idling over 1600 even at a dead stop fully warmed up lol. It doesn't do it all the time though. I can deal with the high idle, the odd stuff it does when decelerating is what bothers me.

Im pretty sure I had that same prob as you though. My TPS had shifted somehow keeping the ECU thinking that I had my foot on the gas. It would make the car stay revved up just like yours. Im pretty sure there should be no signal with teh throttle all the way closed. I was able to tell it was the problem because My safc would show like 1% throttle when my foot wasnt even on the gas. Check to make sure your TPS hasnt moved

I rechecked it last night. I know for a fact that the tps at idle should show between .45 and .55.

subscribing to this thread, this sounds like a problem i have had since i put my motor back in.

it could be that the aac valve or idle air control might sticking on decel have you checked to make sure that your throttle plate completely closes? i had somewhat of a issue lke this before and the little nut on the throttle body was loose and the tiny screw moved up causing my throttle plate to not completely close.

im betting it might be a iacv or aac valve issue that is causing this problem

Yeah the throttle plate is closing all the way. I wondered about the iacv and aac myself, just wondered if anyone else knew anything about it.

the aac valve could not be responding quickly enoug and causing your idle to be slightly high on decel when was the last the iacv or aac vaave was cleaned

also wheb was the last time you set your tps and base idle

It was all cleaned over the winter while I had it apart, and I reset the tps and idle last night. Weird thing about the idle is that it'll randomly idle like it should, then jump up between 1600-2000 rpms and stay there for a while.